My smile is awkward and my lips pull too tight. What treatments would work best for me?

Smiling is very uncomfortable for me. I cannot smile properly when I want/try to, and when I smile naturally, my lips pull tight and flatten out, almost as if they don't know how to form a smile. Another concern I have is that the corners of my mouth are quite droopy. I've considered the fact that my mouth muscles are too overactive and have looked into Botox and filler, but I'm not sure which treatment or of any others treatments that would suit my situation. Any ideas?